"Recovery has been more difficult than I thought. As I write this, it is not clear that I will ever play guitar again," he wrote in a New Year post titled "Bono's A to Z of 2014."

"I personally would very much miss fingering the frets of my green Irish falcon or my (RED) Gretsch. Just for the pleasure, aside from writing tunes," he added.

He said the injury has forced him to cancel all public appearances and communications for the first half of 2015.

U2 said this month they were planning a 2015 tour, set to start in May, which will be the Irish band's first since 2009-2011, which was the highest-grossing tour in history.

After the accident, U2's three other members said they expected the singer to make a full recovery and that the band would be playing again soon.

Bono said he would focus on getting better ahead of the scheduled tour start.

"U2 is a live band. Live is where we live or die... We have some extraordinary ideas up our sleeve for this tour I've just got to be rebuilt by 14th May," he said.

He posted an X-ray photo of his elbow on the band's site, showing several titanium pins connected to his arm bone.

"Here is my titanium elbow for a laugh," he quipped.

He said despite the physical injuries he sustained, the more serious damage was to his ego.

"I broke my hand, my shoulder, my elbow and my face but the real injury this year was to my Irish pride as it was discovered that under my tracksuit I was wearing yellow and black Lycra cycling shorts," he wrote.